Profibus Slave Export Module
This module makes ION register values available in a format that the Profibus master devices can recognize and use. Each module can map and scale up to six ION register values, which are then packaged into a Profibus DP response packet.
The Profibus Slave Export module takes the numeric or Boolean value from Source inputs and makes them available to be read by the Profibus masters. You can link any or all Source inputs to the output registers of other ION modules.
This register specifies whether or not the output values will be scaled. If Scaling is set to yes, then the values in the IonZero, ProfiZero, IonFull and ProfiFull registers are used to scale the output values; if it is set to no, no scaling is performed.
This register specifies the minimum value that can be read by Source inputs. If a Source input is less than IonZero, the value is set to IonZero.
This register specifies the maximum value that can be read by Source inputs. If a Source input is greater than IonFull, the value is set to IonFull.
This register specifies the minimum value that will appear at any Profibus Value output register. If a value is less than ProfiZero, the output is set to ProfiZero.
This register specifies the maximum value that will appear at any Profibus Value output register. If a value is greater than ProfiFull, the output is set to ProfiFull.
There are six Profibus Value output registers, each containing a 32-bit signed integer value. These six values are further translated into the 32-byte block of data that is returned to the Profibus master on request.
All events are recorded in the Event register. Possible events and their associated priority numbers are:
|Event priority group
|Setup register or labels have changed.
The Event output register stores the following information for each ION event: time stamp, priority, cause, effect, and any values or conditions associated with the cause and effect.
Responses to special conditions
The following table summarizes how the module behaves under different conditions.
|Value returned by the Profibus Slave Export Module
|If the Source input is N/A
|After the module is re-linked or its setup registers are changed
|New Value or 0
|When the device is started or powered-up (either the first time, or after a shut-down)
Detailed module operation
Four setup registers (IonZero, IonFull, ProfiZero and ProfiFull) can be used to scale a range of numeric input values to a specified output range. The minimum and maximum values that can be read by the module are specified in the IonZero and IonFull setup registers; the Profibus Value output registers are scaled according to the limits specified in the ProfiZero and ProfiFull setup registers. Input values that fall between IonZero and IonFull are linearly interpolated to within the ProfiZero - ProfiFull limits.
For example, if the Profibus master requires kW data in the 5000kW to 20000kW range, and it is set to provide output values scaled between the range of 0 to 1023; if a value of 15000kW is read the Profibus Value output register reads 682.
Any values for the kW register below 5000kW will be returned to the Profibus Master as a value of 0; any reading in excess of 20,000kW will be returned as a reading of 1023. The Profibus Master must apply the appropriate scaling and offset values necessary to interpret these measurements.
Profibus-DP Messaging Protocol
Profibus is a multi-master/slave communications protocol designed for use in power distribution, manufacturing or process automation. Profibus-DP (Decentralized Periphery) is a performance-optimized protocol that is dedicated to time-critical communications between automation systems and peripherals. Baud rates for the Profibus-DP can range from 9600 bps to 12 Mbps.
Each 32-bit value stored in the Profibus Slave Export output register, as well as in each block of data that the slave returns to the master is represented by a 32-bit signed integer, with values ranging from –2 147 483 648 to +2 147 483 647.
Each block of data that is mapped by the Profibus Slave Export module consists of 8 bytes of setup and control data, plus 24 bytes of data representing the values contained in the ION registers that are linked to this module's inputs. Refer to the ION7300 Profibus DP Serial Communications Protocol Document for information.